diff --git a/code/Model/SiteTree.php b/code/Model/SiteTree.php
index 2ee8e6b1d5..7d2195ed91 100755
--- a/code/Model/SiteTree.php
+++ b/code/Model/SiteTree.php
@@ -1838,7 +1838,7 @@ public function flushMemberCache($memberIDs = null)
         }
     }
 
-    public function validate()
+    public function validate(): ValidationResult
     {
         $result = parent::validate();
 
diff --git a/code/Model/VirtualPage.php b/code/Model/VirtualPage.php
index 1237d3eeec..6a8c664641 100644
--- a/code/Model/VirtualPage.php
+++ b/code/Model/VirtualPage.php
@@ -369,7 +369,7 @@ public function getSettingsFields()
         return $fields;
     }
 
-    public function validate()
+    public function validate(): ValidationResult
     {
         $result = parent::validate();